INVALID_SESSION_ID: Invalid Session ID found in SessionHeader: Illegal Session - php

Question

Similar issues -
INVALID_SESSION_ID using partner/enterprise wsdl for two different SF users - Tried solution but didn't work.
I was trying to use Salesforce PHP toolkit with ZF 2. I have added namespace to php files in salesforce soap client and used it in zend controller.
Added follwing line to all php files in Salesforce SOAP client library.
namespace Salesforce\Soapclient;
Then included it in ZF controller.
use Salesforce\Soapclient;
Here is the connetion code -
$empid = 'e1234567';
$sf_WSDL = 'C:\wamp\www\myapp\app\vendor\salesforce\wsdl\enterprise.wsdl.xml';
$sf_username = $config['salesforce']['username'];
$sf_password = $config['salesforce']['password'];
$sf_token = $config['salesforce']['token'];
/***********/
try {
// Create SOAP client instance
$sfSoapClient = new Soapclient\SforceEnterpriseClient();
// Create connection
$sfSoapClient->createConnection($sf_WSDL);
var_dump($_SESSION['enterpriseSessionId']);
if (isset($_SESSION['enterpriseSessionId'])) {
$location = $_SESSION['enterpriseLocation'];
$sessionId = $_SESSION['enterpriseSessionId'];
$sfSoapClient->setEndpoint($location);
$sfSoapClient->setSessionHeader($sessionId);
} else {
// Login to SF
$sfSoapClient->login($sf_username,$sf_password . $sf_token);
$_SESSION['enterpriseLocation'] = $sfSoapClient->getLocation();
$_SESSION['enterpriseSessionId'] = $sfSoapClient->getSessionId();
}
var_dump($_SESSION['enterpriseSessionId']);
// Get candidate profile by employee id
$candidate_profile = $this->getCandidateTable()->getCandidateByEmpId($empid);
$ids = array();
array_push($ids, $empid);
// If no profile for logged internal employee
if (!$candidate_profile){
$query = "SELECT Id, First_Name__c from Employee__c";
$response = $sfSoapClient->query($query);
echo "Results of query '$query'<br/><br/>\n";
foreach ($response->records as $record) {
echo $record->Id . ": " . $record->First_Name__c . "<br/>\n";
}
}
} catch (Exception $exc) {
//TODO Handle error login exception
die('Connection could not established.');
}
But I'm getting following error -
INVALID_SESSION_ID: Invalid Session ID found in SessionHeader: Illegal
Session
Note that "Lock sessions to the IP address from which they originated" setting is turned off.